why pay fees when mining??

[dirtycat]

stop paying fees! use p2pool!

[Graet]

What is meant by orphans? 

It means that the block has no children blocks. (seriously, in bitcoin terminology, orphan == childless.. brilliant, isn't? )

Lol, indeed, ought be barren blocks.

I think the correct term is "invalid block"
also calling "transaction verification services" "mining" isn't terribly accurate

these are not Bitcoin terms so much as term that have been used by people in Bitcoin and adopted by others until it has become the common though confusing names we have today

For some time the generic name in my country for a 4 wheel drive vehicle was "Jeep" even though there are many 4wd vehicle manufacturers, no manufacturer apart from Jeep were happy with this - but it is still what we said - similar applies here

[Gabi]

I'm sorry but pool fees are only a way for pool owners to profit from the pool. Why should a miner mine for them? 

Keep in mind that, in the long run, "normal" people will not have the infrastructure necessary to run a full node. AFAIK, P2Pool requires you to run a full node. Centralized pools do not have such requirement.

Nothing stops a centralized pool to be part of P2Pool, though. That could be used as a way of saying "look, I follow P2Pool rules, so I can never cheat, not even if I happen to have >50%". But even in such context, the centralized pool would definitely need to make money somehow to pay for the infrastructure demanded by a full node, plus its profits.

Today running a node is not a problem. And doing it actually help the network. And i doubt in the long run it will be a problem, if running a node will require servers and infrastructures then bitcoin will become super-centralized